1. Field of the Invention
The present invention relates to a rewind mechanism for a magnetic tape cassette telephone answering device having a remote playback capability, and to control circuitry useful with such a device. Principles of the invention are set forth in the inventor's Disclosure Document No. 086,397 filed Dec. 7, 1979.
2. Description of the Prior Art
A desirable feature of a telephone answering device is to enable the user to play back previously recorded incoming messages under remote control. Such a facility allows the user, when he is away from his home or office, to call his own telephone number, and when the call has been automatically answered, to transmit a beep tone via the telephone line. Receipt of this beep tone causes the answering device automatically to rewind the incoming message tape, and then to drive the tape forward while picking up and transmitting to the telephone line the earlier recorded messages. The user can thus obtain his messages without first returning to the location of the telephone answering device.
Exemplary mechanisms for implementing such remote controlled playout in a reel-to-reel telephone answering device are set forth in the inventor's U.S. Pat. Nos. 4,104,487; 4,197,426; 4,201,888; 4,213,010; and 4,236,044. In these patents, circuitry and mechanisms are described for detecting the beep tone, and in response thereto, for conditioning the device first to rewind the incoming message tape and then to drive the tape forward while the messages are played out. Systems are also disclosed therein for terminating the remote playout and for reconditioning the device to answer additional calls.
All of the above mentioned patented systems utilize a reel-to-reel tape for recording the incoming messages. The use of a magnetic tape cassette has certain advantages over such a reel-to-reel arrangement. For the same length of tape, a cassette requires less space, thereby enabling size reduction of the device without reducing the number of incoming messages that can be recorded. With a cassette, there is no problem of tape accidently spilling off the reel. Cassettes are easy to handle and replace. If the user should wish to retain the recorded incoming messages, this can be done by simply substituting a new cassette. The outgoing announcement advantageously may be recorded on a re-entrant tape loop cassette.
Prior art remote playout mechanisms are not directly usable in a cassette telephone answering device because of certain constraints imposed by the cassettes themselves. Particularly notable is that the tape is exposed through an open edge of the cassette package. This necessitates the use of a record/playback head and a pinch roller that can be inserted through the open cassette edge into engagement with the tape. In the automatic answering mode of a telephone answering device, the head and pinch roller will normally be operatively positioned in engagement with the tape. Thus when the user signals for remote playout, the record head and pinch roller must be withdrawn from the cassette prior to rewinding the tape. When rewind is complete, the head and pinch roller must be reinserted against the tape to facilitate message pickup and remote playback.
Thus, a rewind mechanism for a tape cassette telephone answering device having remote playout capability must include means for automatically withdrawing the head and pinch roller prior to rewind, and for reestablishing physical contact of the head and pinch roller with the tape when rewind is complete. An object of the present invention is to provide such means.
In a normal cassette mechanism, the record/playback head is mounted on a carriage which is pushed forward into the tape cassette by a cam mechanism which is operated by a pushbutton or rotary knob. The pinch roller normally is spring loaded on a separate bracket so as to bias the tape against the drive capstan with a certain force which is independent of that exerted on the carriage by the cam mechanism. Such an arrangement presents a problem when remote recovery is desired, since it would then be necessary to use the same cam mechanism to withdraw the carriage from the cassette. Another object of the present invention is to overcome this shortcoming by providing a head and pinch roller carriage assembly which differs from the prior art in that the inventive carriage is normally spring biased into contact with the cassette tape, and is retracted away from the cassette alternatively by a manual cam mechanism or by a remotely controlled lost motion linkage. Concomitantly, a further objective of the present invention is to provide a remote controlled rewind mechanism for a tape cassette telephone answering device.
It is also an objective of the present invention to provide certain simplified electrical control circuitry for a telephone answering device. The circuitry facilitates return of the answering device to the standby or off condition from various different modes of operation including the normal answering mode, an "announcement only" answering mode, and a "record announcement" mode.